by Prof Onno Bokhove and Tom Kent, PDRA, University of Leeds
(The University of Leeds is a collaborator on the DARE project).
Motivated by the Boxing Day 2015 floods in Yorkshire (involving the Aire and Calder Rivers), we aim (i) to explore strategies of dynamic flood control and mitigation, and (ii) to assess and communicate flood-mitigation schemes in a concise and straightforward manner in order to assist decision-making for policy makers and inform the general public. To achieve our objectives, we are developing idealised observing system simulation experiments (OSSEs) using novel numerical models based on the Wetropolis flood demonstrator. Wetropolis is a physical model that provides a scientific testing environment for flood modelling, control and mitigation, and data assimilation, and has inspired numerous discussions with flood practitioners, policy makers and the public. Such discussions led us to revisit and refine a procedure that offers both a complementary diagnostic for classifying flood events (from gauge data and/or simulations) and a protocol to optimise the assessment of mitigation schemes via comprehensible cost-effectiveness analyses.
We have developed a protocol that revisits the concept of flood-excess volume (FEV). It is often difficult to grasp how much water is responsible for the damage caused by an extreme flood event, and how much of this floodwater can be mitigated by certain mitigation measures. Our protocol not only quantifies the magnitude of a flood but also establishes the cost-effectiveness of a suite of ‘grey’ engineering-based measures and ‘green’ nature-based solutions. Using river-level gauge data and mitigation schemes from the UK and French rivers, we demonstrate objectively the effectiveness of measures that can help stakeholders make decisions based on both technical and environmental criteria. The protocol should form a preliminary analysis, to be conducted prior to more detailed hydraulic modelling studies. In collaboration with colleagues from Univ. Grenoble, our work has been published in an international journal and further disseminated at numerous meetings and conferences. To date, it has contributed to the EU-funded NAIAD project through our colleagues in France and we are exploring future impact studies internationally. In our recently submitted article, a basic numerical model of Wetropolis is used to determine the relevant time and length scales prior to its construction as a physical model. We are developing the hydrodynamic modelling further, both mathematically and numerically, in order to conduct idealised experiments in flood control and mitigation.
Image ‘FEV concept’
- Bokhove, O., Kelmanson, M. A., Kent, T., Piton, G., & Tacnet, J. M.: Using flood-excess volume to assess and communicate flood-mitigation schemes. EGU general assembly, Vienna, April 2019 (oral). Available online.
- Bokhove, O., Kent, T., de Poot, H., & Zweers, W.: Wetropolis: models for education and water-management of floods and droughts. EGU general assembly, Vienna, April 2019 (poster). Available online.
- Kent, T., Cantarello, L., Inverarity, G., Tobias, S.M., Bokhove, O. (2019): Idealized forecast-assimilation experiments and their relevance for convective-scale Numerical Weather Prediction. EGU general assembly, Vienna, April 2019 (oral). Available online.
- Bokhove, O., Kelmanson, M. A., Kent, T., Piton, G., & Tacnet, J. M.: Public empowerment in flood mitigation, Flood & Coast conference, Telford, June 2019 (oral).
- Bokhove participated in the ‘Landscape decisions’ program at the Isaac Newton Institute, Cambridge (July/August 2019). Web: https://www.newton.ac.uk/event/ebc